Hydroponics has developed from the findings of experiments carried out to determine what substance makes plants grow and the composition of plants. Such work on plant constituents dates back as early as the 1600s. However, plants were being grown in a soil-less culture far earlier than this. Hydroponics is at least as ancient as the Egyptian pyramids. A primitive form has been carried on in Kashmir for centuries. The process of hydroponic growing in our oceans goes back to about the time the earth was created. Hydroponic growing preceded soil growing. But, as a farming tool, many believe it started in the ancient city of Babylon with its famous hanging gardens, which are listed as one of the Seven Wonders of the Ancient World, and was probably one of the first successful attempts to grow plants hydroponically.
Hydroponic gardening probably first became a modem reality around 1940 when the U.S. Army used hydroponic gardening techniques to grow fresh vegetables in the Pacific Islands. NASA was instrumental in advancing the field of hydroponics. They were developing a way to cultivate food in space in the absence of light. One of the major factors was the cost of putting these materials into space. They developed hydroponics systems as they are light, extremely efficient and have high yields. There are a number of fully-fledged hydroponics systems in a number of American nuclear submarines, Russian space stations and various off-shore drilling rigs.
The development of plastics materials freed growers from the costs of constructions associated with the concrete beds and tanks previously used. Beds are now scraped out of the underlying medium and simply lined with a heavy vinyl (20 mm), then filled with growth medium to support the plants. With the development of suitable pumps, time clocks, plastic plumbing and other equipment, the entire hydroponic system can now be automated, or even computerised, reducing both capital and operational costs.
Recently, interest in hydroponics gardening has substantially increased. The reasons for this probably include: firstly some of the major countries of the world continue to have problems producing food under typical conditions—either because of poor weather or poor soil, or both. Secondly, in very populated areas, the availability of land for gardens for the average homeowner is rapidly decreasing. Hydroponic gardening techniques offer the possibility of home-grown food products to the townhouse apartment owner, or the owner of a small home with little land who cannot otherwise have a garden.
There are two main types of hydroponic systems: an open system and a closed system. In the open hydroponic systems, a nutrient solution is periodically fed to the plants supported in an inorganic growth medium. The nutrient solution is drained through the growth medium to the environment. In the closed hydroponic system, the nutrient solution is periodically fed to the plants supported in an inorganic growth medium and then collected and recirculated for further use in later periodic feeling cycles. Closed systems are preferred for being more environmentally friendly, less wasteful of nutrient solution and hence more economic. On the other hand, they suffer from the disadvantage that the recirculated solution deteriorates with each cycle, both in terms of the amount of nutrient available to the plant (which can be topped up) and in terms of the amount of waste products and contaminants that build up, necessitating periodic flushing-out and cleaning of the closed system.
A typical example of a hydroponics system usable in either open or closed forms comprises a plant supporting chamber having an inert growth medium therein; a collection reservoir positioned below the plant supporting chamber; a pump reservoir for containing a nutrient solution; and a valve/connection system delivering the nutrient solution to the plant supporting chamber and for operating the system in either open or closed forms.
However, the presence of the inert, plant growth medium in such hydroponics systems gives rise to problems that have an adverse effect on the system and, in particular, the plant and its growth. Such problems include build-up of inorganic salts or other plant waste, fluctuations in nutrient available, root rot and excessive root growth. Other problems include build-up of algae and widely fluctuating pH of the nutrient solution due to accumulation of waste in stagnant pockets of nutrient solution. Therefore, there is a need for a simple system that avoids these problems, yet that provides an appropriate environment for growing plants without soil.